The present invention relates to a pattern generating system for use in electronic sewing machines, which is designed to store data relating to the bight movement of the needle and to the feed movement of the feed dog in a static memory and read out said data in timed relation to the rotation of the main shaft of the sewing machine, said data thus read out from said static memory being given to a drive unit which controls the amount and direction of said bight and feed, thereby enabling pattern stitching to be carried out.
The applicants have previously provided a pattern signal generating system for electronic sewing machines, in Japanese Patent Application No. 149614/1977, wherein the bight data relating to the bight movement of the needle and the feed data relating to the feed movement of the feed dog are separately stored in a static memory, said bight date or feed data being composed of output-oriented data relating to the amount of bight or feed and order instruction-oriented data relating to the order in which said output-oriented data is read out, the arrangement being such that the bight data and feed data for forming a predetermined stitch pattern can be read out in a predetermined order in timed relation to the bight and feed movements. In said prior system, however, the relation between said static memory for storing bight data and feed data and the control system is such that with respect to a particular program stored in the static memory, a particular control system line for giving an instruction to read out said program is specified. Thus, the programs stored in the static memory are in inseparable relation to the control system lines.